In the past, since a hydraulic elevator requires a long piston rod, short sections of tubing have been joined together at the site so as to produce this long piston rod or piston which is moved vertically in the elevator shaft for lifting and lowering an elevator in the building. Hydraulic fluid is employed for actuating this piston rod.
Since the piston rod must be retracted into the cylinder for a substantial distance, care must be taken to assure that each section of the piston rod or piston is of the same diameter and that the sections of tube or pipe which make up the piston rod are aligned in coaxial relationship and there is a smooth transition from one piston rod to the next along the periphery of such sections. At times, it is necessary to disassemble these sections of tube or pipe so as to replace a particular section.
In the past, such joining of sections of tube or pipe together to form an extended piston rod have usually employed either welding or the clamping of tube or pipe sections together. Both processes are quite time consuming and require special tools and skilled labor in order to assemble properly.